Viral respiratory tract infection is the most common illness in humans and the economic cost for non-influenza-related viral respiratory tract infection approaches $40 billion in the US (Fendrick A M et al., 2003), while influenza causes tens of millions of day of restricted activity, bed disability and work loss (Sullivan K M et al, 1993). There is also the ever present threat of a pandemic flu outbreak and the apparent unstoppable AIDS virus spreading far and wide. With the ability of viruses to mutate by genetic drift and genetic shift, new viruses that are not susceptible to existing vaccines will continue to come into being. There is, therefore, a need to develop more effective antiviral drugs.
Another medical condition, prolonged or chronic hyperglycemia, wherein blood glucose levels are elevated from long periods, produces many detrimental effects. This condition is exemplified by diabetes. Diabetes exacts a huge toll in money and human suffering, accounting for more than 100 billion dollars of healthcare costs annually in the United States (DiRamond J, 2003). The number of cases worldwide is estimated at 150 million with an equal number of undiagnosed cases in the First World countries and eight times more undiagnosed cases in the Third World (Levitt N S et al, 1993). The disease is characterised by high blood sugar (glucose) resulting from the defects in either insulin secretion or decreased sensitivity of the body's cells to the action of insulin, leading to a condition of hyperglycemia. Type I diabetes is currently treated by preprandial administration of exogenous insulin and dietary restriction. Current therapy of type 2 diabetes includes lifestyle modifications and the use of a variety of pharmacological agents that aim to increase insulin secretion, decrease hepatic glucose production, and/or increase insulin actions. Despite these approaches, good glycemic control is beyond the reach of most diabetic individuals, and the state of prolonged or chronic hyperglycemia can cause cardiovascular diseases, stroke, blindness, kidney failure, neurological dysfunction, necrosis and gangrene of extremities. The search for better and more specific agents with physiological properties for hyperglycemia is highly warranted.
Accordingly, any new and improved treatment of viral infections and/or conditions relating or due to hyperglycemia will be welcome.
The compound des-aspartate-angiotensin I is an endogenous angiotensin peptide (Sim M k et al, 1994, a,b). It is formed or derived from angiotensin I by a specific aminopeptidase present in blood vessels and the hypothalamus (Sim M K, Qui X S, 1994). Previous studies suggested the use of des-aspartate-angiotensin I in cardiovascular and renal actions (Sim U.S. Pat. Nos. 5,773,415, 6,100,237, 6,589,938B2 and US2003/0086920). However, no further uses are taught or suggested for des-aspartate-angiotensin I.